Azidofluoroalkylation of Alkenes with Simple Fluoroalkyl Iodides Enabled by Photoredox Catalysis

Perfluoroalkylative pyridylation of alkenes via 4-cyanopyridine-boryl radicals

A metal- and photo-free method for the perfluoroalkylative pyridylation of alkenes has been developed.

A metal-free and photo-free method for the perfluoroalkylative pyridylation of alkenes has been developed via a combination of computational and experimental studies. Density functional theory calculations and control experiments indicate that the homolysis of R_f–X (X = Br, I) bonds by the 4-cyanopyridine-boryl radicals in situ generated from 4-cyanopyridine and B₂pin₂ is the key step. Sequential addition of R_f radicals to alkenes and the selective cross-coupling of the resulting alkyl radicals and 4-cyanopyridine-boryl radicals gives alkene difunctionalization products with a quaternary carbon center. This method exhibits a broad substrate scope and good functional group compatibility.

Iron-catalyzed carboazidation of alkenes and alkynes

Carboazidation of alkenes and alkynes holds the promise to construct valuable molecules directly from chemical feedstock therefore is significantly important. Although a few examples have been developed, there are still some unsolved problems and lack of universal methods for carboazidation of both alkenes and alkynes. Here we describe an iron-catalyzed rapid carboazidation of alkenes and alkynes, enabled by the oxidative radical relay precursor t-butyl perbenzoate. This strategy enjoys success with a broad scope of alkenes under mild conditions, and it can also work with aryl alkynes which are challenging substrates for carboazidation. A large number of diverse structures, including many kinds of amino acid precursors, fluoroalkylated vinyl azides, other specific organoazides, and 2H-azirines can be easily produced.

Carboazidation of alkenes and alkynes holds the promise to construct valuable, functionalized molecules. Here, the authors report a general and efficient iron-catalyzed carboazidation of both alkenes and alkynes enabled by t-butyl perbenzoate.

Solvent-tuned chemoselective carboazidation and diazidation of alkenes via iron catalysis

A solvent-tuned chemoselective carboazidation and diazidation of alkenes with CH₂Cl₂ and TMSN₃ through iron catalysis has been described.

Intermolecular, redox-neutral azidoarylation of alkenes via photoredox catalysis

An intermolecular, redox-neutral azidoarylation of alkenes with pyridines and TMSN₃ has been reported via visible light-induced photoredox catalysis.

Efficient access to unprotected primary amines by iron-catalyzed aminochlorination of alkenes

Primary amines are essential constituents of biologically active molecules and versatile intermediates in the synthesis of drugs and agrochemicals. However, their preparation from easily accessible alkenes remains challenging. Here, we report a general strategy to access primary amines from alkenes through an operationally simple iron-catalyzed aminochlorination reaction. A stable hydroxylamine derivative and benign sodium chloride act as the respective nitrogen and chlorine sources. The reaction proceeds at room temperature under air; tolerates a large scope of aliphatic and conjugated alkenes, including densely functionalized substrates; and provides excellent anti-Markovnikov regioselectivity with respect to the amino group. The reactivity of the 2-chloroalkylamine products, an understudied class of amphoteric molecules, enables facile access to linear or branched aliphatic amines, aziridines, aminonitriles, azido amines, and homoallylic amines.

Transition-Metal-Free Three-Component Radical 1,2-Amidoalkynylation of Unactivated Alkenes

A transition-metal-free radical 1,2-amidoalkynylation of unactivated alkenes is presented. α-Amido-oxy acids were used as amidyl radical precursors, which were oxidized by an organic photoredox catalyst (4CzlPN). The electrophilic N-radicals chemoselectively reacted with various aliphatic alkenes and the adduct radicals were then trapped by ethynylbenziodoxolone (EBX) reagents to eventually provide the amidoalkynylation products. These transformations, which were conducted under practical and mild conditions, showed high functional group tolerance and broad substrate scope. Mechanistic studies supported the radical nature of these cascades.

Iron(II)-Catalyzed Azidotrifluoromethylation of Olefins and N-Heterocycles for Expedient Vicinal Trifluoromethyl Amine Synthesis

We report herein an iron-catalyzed azidotrifluoromethylation method for expedient vicinal trifluoromethyl primary-amine synthesis. This method is effective for a broad range of olefins and N-heterocycles, and it facilitates efficient synthesis of a wide variety of vicinal trifluoromethyl primary amines, including those that prove difficult to synthesize with existing approaches. Our preliminary mechanistic studies revealed that the catalyst-promoted azido-group transfer proceeds through a carbo-radical instead of a carbocation species. Characterization of an active iron catalyst through X-ray crystallographic studies suggests that in situ generated, structurally novel iron-azide complexes promote the oxidant activation and selective azido-group transfer.

Alkene 1,2-Difunctionalization by Radical Alkenyl Migration

Transition-metal-free radical α-perfluoroalkylation with the accompanying vicinal β-alkenylation of unactivated alkenes is presented. These radical cascades proceed by means of 1,4- or 1,5-alkenyl migration by electron catalysis on readily accessed allylic alcohols. The reactions comprise a regioselective perfluoroalkyl radical addition with subsequent alkenyl migration and concomitant deprotonation to generate a ketyl radical anion that sustains the chain as a single-electron-transfer reducing reagent.

Photo-induced, Cu-catalyzed three component azidofluoroalkylation of alkenes with CF3I and RfI as fluoroalkylation reagents

Under UV light irradiation, the Cu-catalyzed azidofluoroalkylation of alkenes was realized by directly using fluoroalkyl iodides as fluoroalkylation reagents.

Fe-Catalyzed three-component carboazidation of alkenes with alkanes and trimethylsilyl azide

Iron out the difference. Carboazidation of alkenes using cycloalkanes, CH₂Cl₂, CHCl₃ and CCl₄ as alkylating reagents proceeded smoothly in the presence of TMSN₃, DTBP and a catalytic amount of Fe(acac)₃ to afford chain extended alkyl azides and γ-azido chloroalkanes in good to high yields.